Counterbalance for crank shafts



June 15 1926. 1,588,784

W. C; TROUT COUNTERBALANGE FOR CRANK SHAFTS Filed 00: 12, 1925 .Tvo u t Q M Patented June 15, 192 6 j UNITED STATES wan'raa onannas moor, 01.1mm, 'rma counrnamtmca roa mm: sums. 1

Applicatlon'nled. October 12, 1925. Serial No. 61377;"

My invention relates to a counter-balance for use on a crank shaft. 'It is particularly adaptable for use on pumping rigs for deep wells. v It is the purpose of my invention to pro:

. 'vide a means for counter-balancing the weight of the pump rod in the pumping of deep wells; and to so construct the device that it may be applied to the crank employed in operatin the walking beam, jack, or other pump ro reciprocating means. It is also desired to make the counter-balance adjustable so as to adapt it for use in balancing the weight of different loads.

Referring to the drawing herewith, Fig.

7 1 shows a side view, partly in elevation, of

a crank arm embodying my invention, certain parts being broken away for greater clearness. Fig. 2 is a top plan view there of. Fig. 3 isa side elevation of a pumping unit illustrating the use of my invention. Fig. 4 is a transverse section on the line 4-4. of Fig. 1. Like numerals of reference designate like parts in all the views.

I have illustrated my invention as applied to a standard pumping unit but it is to be understood as adaptable for other uses. The

pump rod 1, having the load of the plunger and the fluid thereon, is reciprocated through the walking beam 2, the pitman 3, and crank arm 4, secured upon the crank shaft 5. The

- crank shaft may be rotated through a band wheel 6, as shown.

The weight of the pump rod and its load resists the rotation of the crank arm on the up stroke of the rod and assists the rotation of said crank arm on the 'down stroke.

The result is a jerking motion upon the in-- stallation when the pump rod drops. To

, overcome this, I form the crank arm so as to accommodate a weight 7 adjustable along said arm, to counterbalance the weight of j the rod and its load. m The crank arm has an opening 8 therein to fitabout the-shaft 5, said openin being formed along the axial center oft e arm and at a point thereon spaced from the inner end 9, but at a p the outer end 10, thus orming a short inner arm and a long outer arm. The longer arm has spaced openings 12 thereln for attach-.'

reater distance from 3 closed at bot-h end's and the ends of the arm are extended outwardlyaway from the same to form flanges or stops 14 and 15. The groove of the mortice also has a wide mouth 16 cut therein intermediate the ends to admit the heads 17 of the bolts 18, by

means of which the weights 7 are secured.

to the arm.

The weights 7 are preferably flattened heavy plates of approximately the same thickness as the arm, one end 19 of each weight is extended and bored to form an opening to receive the bolt 18; the other end of the weights is recessed and formed with an opening to receive the other bolt 18.

There are nuts on each bolt so that the weights may be clamped in an adjusted position along the arm- It wil be noted that the heads of bolts 18 may be inserted into the slot through the openlng or' mouth 16 and adjusted to the desired position and the weight may then be secured thereto. The weight may then be adjusted to any desired position and the nuts tightened to clamp the. weight in that position. There are two weights 7 shown, although but one may be employed, if desired. The weights may be placed at the extreme end of the arm 4 when the weight of a heavy load is to be balanced. If a small load is being handled the weights may be adjusted to a point nearer the shaft. When no weight is on the beam the weights may be moved to be in aline on each side of the shaft as shown in dotted lines in Fig. 1. This is desirable when the device is employed to raise rods from the'well for repairs, or for running when the pitman is detached.

The placing of the counter weight upon the crank shaft in such manner that it may be adjusted to any desired position is of marked advantage and makes it possible to operate the pump with a minimum of vibration and shock which would result from an otherwise unbalanced action of the pump rod. The weights are readily attached and adjusted and may be removed without difficulty.

What I claim as new and desire to protect by Letters Patent is:

1. In a device of the character described,

' a crank shaft, means to rotate said shaft,

a crank arm. on said shaft extending unequal distances each side thereof to form long andshort arms, a wrist pin adjustable along said long arm, said crank opposite undercut mortices, bolts having heads slidable in said mortices and weights secured on said bolts to be thereby clamped in any desired position along said crank arm.

2. In a device of the character described, a crank shaft, a crank arm thereon having a morticed groove cut therein, said groove being closed at the ends thereof, but having a mouth therein between its ends, bolts having their heads slidable in said groove, and a wei ht on said bolts and adjustable to desire ositions along said arm in the I manner escribed.

3. In a device of the character described, a crank shaft, a crank arm thereon having mortices cut on its forward and rear sides, weights slidable along said mortices and means to clamp said weights at various adjusted positions along said arm to a position on op osite sides of said shaft.

4. In a evice of the character decribed, a crank shaft, a crank arm on said shaft, a wristpin adjustable alon said arm, said arm having undercut mortices on its forward and rearward sides,- bolts havin heads slidable in said grooves, and weig ts on said bolts adapted to be clamped thereby at desired positions along said crank arm for the purpose described.

In testimony whereof I hereunto aflix my signature this 5th day of' October, A. D. 1925.

WALTER CHARLES TROUT. 

